Why Glacier Collapse Behind Nepal's Flash Flood Has Became a Warning Sign for the Himalayas

Nepal is still reeling from the aftermath of deadly flash floods that killed over 350 people on Wednesday. Hundreds of people are still missing and rescue teams are racing against time to search for survivors amid the mountain of debris left behind by flash floods in Nepal’s Nuwakot and Rasuwa districts.

According to scientists, the flash flood in the Trishuli River was caused by the collapse of a glacier across the border in Tibet, not an earthquake as originally thought. Based on seismic and satellite data, as well as videos of the event, scientists say the chain of events began after the bedrock gave way, causing a very large portion of the glacier to collapse.

Seismic waves equivalent to a magnitude 5.2 earthquake

According to the US Geological Survey, the impact generated seismic waves equivalent to a magnitude 5.2 earthquake, and large amounts of ice and rock may have plunged into the Lhende Khola, a tributary of the Bhote Koshi River.

Quick answers to key questions

•5 QUESTIONS

The flash flood was caused by the collapse of a glacier in Tibet, triggered by a failure of the bedrock beneath the glacier, leading to a significant ice avalanche.

The collapse is alarming because it highlights the increasing frequency of such events due to climate change, which is accelerating the melting of glaciers and increasing the risk of natural disasters in the region.

Scientists use seismic and satellite data along with video evidence to analyze the event, identifying the glacier’s collapse and its subsequent effects on local waterways.

Yes, experts warn that the conditions created by climate change and the instability of glaciers suggest that similar incidents could occur more often in the future.

Climate change is causing the melting of Himalayan glaciers to accelerate, resulting in an increased risk of natural disasters and threatening the water systems vital to billions of people.

Read also | Nepal floods: How many people are missing from India, USA and UK? Complete list here

“What we definitely confirmed was a large ice avalanche, probably a mixture of ice and rock, that separated and then became liquid and then turned into this devastating flood,” Simon Allen, a researcher at the University of Zurich who studies glacial hazards in the Himalayas, told Bloomberg.

Rijan Bhakta Kayastha, a climate researcher and professor at Kathmandu University, told The Kantipur Post that the avalanche appeared to have blocked the Lhende River before the blockade was lifted.

“We suspect that an avalanche on the Nepalese side has blocked the Lhende River,” Kayastha said. “There was an earthquake around the same time, but we don’t know yet if it helped trigger the avalanche.”

Climate change is behind the increase in natural disasters

In recent years, Nepal and neighboring countries, including India, Bhutan, China and Pakistan, which share the Himalayas, have seen an increase in natural disasters linked to global warming and climate change.

Read also | Climate change is turning Assam’s monsoon floods into an annual disaster

The Himalayas, the youngest mountain system on Earth, are highly vulnerable to global warming, leading to rapid loss of snow cover.

In March this year, the International Center for Integrated Mountain Development (ICIMOD) said in a report that glaciers in the Hindu Kush Himalayas (HKH) are melting at an accelerating rate, with the rate of ice loss doubling since 2000.

“HKH has the largest volume of ice outside the poles, with an inventory of more than 63,700 glaciers covering nearly 55,782 square kilometers. These glaciers are the source of at least ten major Asian river systems that support food, water, energy and livelihood security for billions. However, approximately 78% of this glacial area, above the 500.00 level, is between 4 meters and 600,000 exposed altitude-dependent warming,” he noted.

China warns of more flooding

Following the collapse of a glacier in Nepal, China’s Ministry of Water Resources issued a warning on Thursday that a major barrier lake had formed near the confluence of the Chhochen Khola and Purepu Tsangpo rivers.

According to China Central Television, an additional 3 million cubic meters of water is expected to flow into the lake over the next three days, posing a high risk of a breach.